Magnetic field driving means for frequency responsive apparatus having a plurality of energy transmittable magnetizable fibers



3550 M) AMA- mm XFR 3 W 1 3 w 5572 Nov. 26, 1968 c. E. BURKLUND 3,413,572

MAGNETIC FIELD DRIVING MEANS FOR FREQUENCY RESPONSIVE APPARATUS HAVING A PLURALITY OF ENERGY TRANSMITTABLE MAGNETIZABLE FIBERS Filed Sept. 1, 1965 2 Sheets-Sheet 1 SIGNAL 12 7 CURRENT LIGHT INPUT INVENTOR. CARL E. BURKLUNO ATTORNEY A A. A in: i M 31:01am.

Nov. 26. 1968 c. BURKLUN 3,413,572

MAGNETIC FIELD DRIVING ME FOR FREQUE RESPONSIVE APPARATUS HAVING A PLURALITY OF ENERGY TRANSMITTABLE MAGNETIZABLE FIBERS Filed Sept. 1, 1965 2 Sheets-Sheet u INVENTOR.

/ 3 2 CARL E. BURKLU/VD A TTO/P/VEY United States Patent MAGNETIC FIELD DRIVING MEANS FOR FRE- QUENCY RESPONSIVE APPARATUS HAVING A PLURALITY OF ENERGY TRANSMIITABLE MAGNETIZABLE FIBERS Carl E. Burklund, Port Washington, N.Y., assignor to Sperry Rand Corporation, a corporation of Delaware Filed Sept. 1, 1965, Ser. No. 484,346 4 Claims. (Cl. 332--26) ABSTRACT OF THE DISCLOSURE An assembly of energy transmitting magnetizable fibers disposed in a first magnetic field for inducing magnetic poles on the extremities of the fibers and a second modulating magnetic fielddisposed substantially perpendicular to the first magnetic field for driving the fiber extremities primarily as a function of the second modulating magnetic field.

This invention relates to signal responsive apparatus and particularly to apparatus responsive to the various frequency components of oscillatory signals.

In accordance with the present invention, apparatus responsive to oscillatory signals comprises one or more unitary assemblies of energy-transmitting fibers arranged in a prescribed geometrical pattern in relatively spaced generally parallel relationship and individually having a preselected frequency response for vibrating at individual preselected frequencies so that at least one portion of each fiber, for example, an end thereof is free to vibrate, an energy source, means for vibrating the assembly in accordance with the oscillatory signals, and an energy receiving device responsive to the energy transmitted by the fibers and a correlating or memory means disposed between the fibers and the energy receiving device.

Preferably, the unitary assembly includes a large number of fibers and the present invention is particularly concerned with means for driving the fibers to cause them to vibrate in response to the oscillatory signal.

Previously, as shown in U.S. patent application Ser. No. 185,064, entitled Frequency Responsive Apparatus of R. D. Hawkins, filed Apr. 4, 1962, issued Oct. 19, 1965 as Patent No. 3,213,197, an electromechanical transducer such as a piezo-electric crystalline material caused the fibers to vibrate when an oscillatory voltage was applied to the transducer electrodes. In lieu thereof, the present invention provides direct force deflection of the fibers constituting the unitary assembly by means of magnetostatic principles utilized in conjunction with magnetizable energy-transmitting fibers.

In addition to advantages such as lower unit cost and lighter weight when used with a plurality of assemblies, the present invention has more accurate modulation capability and also provides predetermined controlled forces to certain fibers or groups of fibers within aparticular assembly.

It is a primary object of the present invention to provide signal responsive apparatus utilizing magnetostatic driving means for applying forces to magnetizable fibers.

It is an additional object of the present invention to provide a modulating type of direct force deflection of the energy-transmitting fibers in a frequency responsive system.

These and other objects are achieved by disposing an assembly of energy-transmitting magnetizable fibers in a first magnetic field for inducing magnetic poles on said fibers and for providing a second modulating magnetic field disposed substantially perpendicular to said first mag netic field for driving the fibers primarily as a function of said second modulating magnetic field Referring to the dawings:

FIG. 1 is a simplified schematic diagram in section showing an assembly of energy-transmitting magnetizable fibers subjected to first and second orthogonally disposed magnetic fields;

FIG. 2 is a schematic diagram in perspective showing a plurality of assemblies having fibers subjected to first and second orthogonally disposed magnetic fields; and

FIG. 3 is an enlarged cross-section of FIG. 2 taken along lines 3-3.

When a fiber of magnetic material or one coated with magnetic material is placed in a constant magnetic field, magnetic poles are induced on the fiber ends. The appearance of magnetic poles is caused by an alignment of the magnetic dipoles present in the material. As the constant magnetic field strength is increased, the alignment improves until a maximum is reached called saturation which produces the maximum induced pole on the fiber. By applying a transverse magnetic field which is perpendicular to the first magnetic field and to the longitudinal axes of the fibers, a force is provided on the induced magnetic pole of the fiber. With the fibers cantilevered, this force is applied perpendicular to the fibers at the ends thereof, each of which is equivalent to the end of a cantilevered beam. The force varies as a function of the transverse magnetic field strength. Thus, a deflection force linearly related to an input signal can be provided by utilizing a first magnetic field of constant field strength disposed parallel to the longitudinal axes of the fibers and a second magnetic field modulated in accordance with the input signal disposed perpendicular to the first magnetic field and the longitudinal axes of the fibers, as will be more fully appreciated by referring to FIG. 1.

As shown in the cross-sectional view of FIG. 1, a unitary array or assembly 10 of energy-transmitting fibers 11 is arranged in a prescribed geometrical pattern in order that the fibers 11 are relatively spaced with respect to each other and generally parallel and individually have. a preselected frequency response differing from that of other fibers in the array 10 for vibrating at individual preselected frequencies as disclosed in said US. patent application Ser. No. 185,064 and in US. patent application Ser. No. 284,712 entitled Frequency Responsive Ap paratus of R..D. Hawkins, filed May 31, 1963.

In accordance with the present invention, the fibers 11 are of a magnetizable material such as pure iron or. preferably 45% cobalt and 55% iron or any other magnetic material which has a high saturation induction since the driver power varies inversely as the square of this quantity. In the event the fibers 11 have a transparent cord} such as quartz for light transmission purposes, at leastl a portion of each fiber 11 is coated with a thin layer of s magnetic material, for example, by electroplating, vapor deposition, or other suitable coating technique. The magnetic coating is then removed from the ends of each of the fibers 11, for example, to permit light to be trans mitted through the fibers. The coating on the ends of the fibers 11 may be removed by the technique disclosed in US. patent application Ser. No. 285,551 entitled, Meth- 0d of Making Frequency Responsive Device, of R. D.

, Hawkins et al., filed May 31, 1963, issued July 25, 1967 as Patent No. 3,333,278 for example which also discloses methods of making the array 10.

An electromagnetic field generating means such as a permanent magnet 12 provides a constant magnetic field as indicated by the solid lines and arrows between its North and South poles 13 and 14, respectively. The array 10 is disposed between the North and South poles 13 and 14 with the longitudinal axes of the fibers 11 aligned parallel to the constant magnetic field of the permanent magnet 12 in order that a magnetic pole is induced on each of the fiber ends 15. An alternating electromagnetic field generating means 20 has spaced upper and lower deflection coils 21 and 22, respectively, that are disposed on opposite sides of the fibers 11 for generating an alternating magnetic field substantially perpendicular to the longitudinal axes of the fibers 11 and to the constant magnetic field provided by the permanent magnet 12. The alternating magnetic field is indicated by the dash lines and arrows and it is modulated in accordance with an input signal provided by a signal source 40. The modulating magietic field causes a force on the induced poles that is applied perpendicular to the fibers 11 at their respective ends 15. With a constant magnetic field applied by the permanent magnet 12 to provide an induced pole having a pole strength independent of time, the force on the induced pole when the alternating magnetic field is generated by a deflection coil carrying the input signal current is directly proportional to the input signal. The force on each of the fibers 11 is then substantially equal .to the induced pole strength times the perpendicularly applied modulating magnetic field strength thus providing a magnetostatic means of driving the fibers 11.

Referring now to FIG. 2, a preferred embodiment of the present invention which incorporates the principles explained above is shown with like elements being represented by like reference characters. A plurality of arrays or assemblies A, 10B, 10C and 10D (hidden) each having a relatively large number of energy-transmitting fibers 11A, 11B, 11C and 11D respectively are disposed in spaced relation with respect to each other. Only four arrays 10A to D are shown in FIG. 2 for purposes of example, normally a large number of them would be utilized in a typical spectrum analyzer. Each of the arrays 10A to D has a contoured base 25A to D respectively having an internal contour or interface indicated by the dash line in order that the fibers 11A to D extend in I cantilevered fashion from their respective bases 25A to D and have individual preselected frequency response characteristics as explained in said U.S. patent application Ser. No. 284,712 and U.S. Patent No. 3,213,197. For purposes of example, the invention will be described with respect to light transmitting fibers having a light source indicated by the legend adjacent to the respective bases 25A to D which provides light rays as indicated by the arrows. The light is transmitted through each of the bases 25A to D and the fibers 11A to D to impinge upon respective masks 26A to D disposed adjacent free ends A to D of the fibers 11A to D with respect to each of the assemblies 10A to D. Light sensitive detectors 27A to D such as photocells are responsive to the light transmitted through the masks 26A to D respectively and provide output signals on their respective leads 28A to D in accordance therewith to respective signal utilization devices not shown as explained in greater detail in said U.S. patent No. 3,213,197. Each of the'masks 26A to D may be acceptance, rejection or any other suitable type as disclosed in said U.S. patent application Ser. No. 284,712 and U.S. Patent No. 3,213,197.

Referring to FIGS. 2 and 3, the four arrays 10A to D are disposed with 10A and 10B substantially coplanar and side-by-side with their high frequency, i.e., shorter, cantilevered fibers 11A and 11B adjacent to each other for reasons to be explained. The arrays 10C and 10D are similarly arranged coplanar and side-by-side but beneath the arrays 10A and 10B, respectively, with their high fre quency cantilevered fibers 11C and 11D adjacent to each other. A permanent magnet 12 has a first south pole piece 30- extending transversely across. the upper portions of the fibers 11A and B of the arrays 10A and 103.. A simi-.

lar second south pole piece 31 extends transversely below the fibers 11A and 11B of the arrays 10A and 10B and above the fibers 11C and 11B of the arrays 10C and 10D,

respectively, while a third south pole piece 32 extends transversely beneath the fibers 11C and 11D of the arrays.

30 and extends transversely across the arrays 10A and 10B spaced above the fiber ends 15A and B. Similarly, a second north pole piece 34 is cooperative and coplanar with the second south pole piece 31 and extends transversely across the arrays 10A, B, C and D spaced below the fiber ends 15A and B above the fiber ends 15C and D. Further, a third north pole piece 35 is cooperative and coplanar with the third south pole piece 32 and extends transversely across the arrays 10C and D spaced below the fiber ends 15C and D. Preferably, the south pole pieces 30, 31 and 32 are stacked in spaced relation one below the other and similarly the north pole pieces 33-, 34 and 35 are also vertically stacked in spaced relation. By this arrangement, the fiber ends 15A and B are subjected to a constant magnetic field that is substantially parallel to the longitudinal axes of. the fibers 11A and B as indicated by the solid line arrows in FIG. 3 from the south pole pieces 30 and 31, cooperating with the corresponding north pole pieces 33 and 34. Similarly, the fiber ends 15C and D are subjected to a constant magnetic field from the south pole pieces 31 and 32 cooperating with their associated north pole pieces 34 and 35. The constant magnetic fields induce magnetic poles at the respective ends 15A to D.

An alternating or modulating magnetic field substan-- tially perpendicular to the above-described constant mag= netic field is provided by three deflection coils disposed intermediate the north and south pole pieces. Deflection coil 21 is located between the south and north pole pieces 30 and 33 respectively and extends transversely above the upper portions of the fiber ends 15A and B of the arrays 10A and 10B, respectively. Deflection coil 22 is located between the south and north pole pieces 31 and 34 respectively and extends transversely below the lower portion of the fiber ends 15A and B and above the fiber ends 15C and D. Deflection coil 23 is located between the south and north pole pieces 32 and 35 and extends transversely beneath the fiber ends 15C and D. The deflection coils consist of elliptically shaped layers, one within the other. The fiber ends 15A and 15B are approximately centered between the cooperative deflection coils 21 and 22 while the fiber ends 15C and 15D are approximately centered between the cooperative deflection coils 22 and 23. The deflection coils 21, 22 and 23 provide an alternating or modulating magnetic field as shown by the dotted arrows with respect to the fiber ends 15A, 15B, 15C and 15D that is substantially perpendicular to the longitudinal axes of the fibers 11A. to D and to the constant magnetic field established by the pole pieces 30 to 35. The deflection coils 21, 22 and 23 are connected by means of respective leads to an AC. input signal source 40.

Preferably, the deflection coil layers 42 are nested concentrically in order to provide a higher intensity alternating magnetic field with respect to the higher frequency fibers 11A to D, i.e., those with the shorter cantilevered free length, and progressively lower intensity alternating magnetic field with respect to the lower frequency fibers, i.e., those having the longer cantilevered free length.

In operation, the constant magnetic field provided by the pole pieces 30-35 causes magnetic poles to be induced in the fiber ends 15A to D. Upon the application of an alter nating magnetic field, a force is produced with respect to the fiber ends 15A to D by the orthogonally disposed alternating magnetic field that is proportional to the amplitude of the input signal from the source 40. This causes vibra= tion of certain of the fibers 11A to D. Depending upon the type of mask 25A to D used, deflection of certain of the fiber ends 15A to D produces a characteristic amount of light passing through the respective masks 26A to D which is received by the respective light responsive detectors 27A to D. An output is therefore provided from the de= tectors 27A to 27D that is correlated with respect to the input signal and suitable for use in spectrum analyzers, pattern recognition apparatus, etc.

While the invention has been described in its preferred embodiments, it is to be understood that the words which. have been used are words of description rather than limitation and that changes within the purview of the appended claims may be made without departing from the true scope and spirit of the invention in its broader aspects.

What is claimed is:

1. In combination,

(1) a unitary assembly of energy-transmitting magnetiza'ble fibers arranged in a prescribed geometrical pattern in relatively spaced generally parallel relationship and individually having a preselected frequency response differing from that of others for vibrating at individual preselected frequencies over a predetermined frequency range,

(2) a magnetic field generating means for providing a constant magnetic field for inducing magnetic poles on said fibers, and

(3) an electromagnetic field generating means for providing a modulating magnetic field disposed substantially perpendicular to said constant magnetic field 'for driving said fibers,

(4) said electromagnetic field generating means includ ing further means for providing said modulating mag" netic field with increasing field strength in the higher frequency range.

2. In combination,

( 1) a plurality of unitary assemblies of. cantilevered energy-transmitting magnetizable fibers arranged in a prescribed geometrical pattern with their longitudinal axes generally parallel and relatively spaced and in dividually having a preselected frequency response differing from that of others for vibrating at individual preselected frequencies over a predetermined tre= quency range as a function of their respective free lengths,

(2) each pair of said assemblies being disposed sub stantially coplanar and with their high. frequency regions adjacent to each other,

(3) a magnetic electromagnetic field generating means for providing a first magnetic field disposed parallel to the longitudinal axes of said fibers of said each pair of assemblies for aligning the magnetic dipoles in said fibers, and

(4) an electromagnetic field generating means for providing a second magnetic field disposedsubstantially perpendicular to the longitudinal axes of said fibers of said each pair of assemblies for driving said fibers primarily as a function of said second magnetic field.

3. In a combination of the character recited in claim 2 in which said electromagnetic field generating means includes further means for providing said second magnetic field with increasing field strength in the higher frequency range of said adjacent high frequency regions.

4. In combination,

(1) a unitary assembly of energy-transmitting magnetizable fibers arranged in a prescribed geometrical pattern in relatively spaced generally parallel relationship and individually having a preselected frequency re sponse differing from that of others for vibrating at individual preselected frequencies over a predeter mined frequency range,

(2) a magnetic field generating means for providing a constant magnetic field for inducing magnetic poles on said fibers, and

(3) an electromagnetic field generating means for providing a modulating magnetic field disposed substantially perpendicular to said constant magnetic field for driving said fibers,

(4) said electromagnetic field generating means including further means for providing said modulating magnetic field with increasing field strength in the higher frequency range,

(5) said further means including nested electromagnetic field generating coils having the greatest number of layers of said coils cooperative with the highest frequency range.

References Cited UNITED STATES PATENTS 2,126,562 8/1938 Lakatos 178-43 2,250,100 7/1941 Hubbard. 2,348,352 5/1944 Mallina 84-115 X 2,542,271 2/1951 Alvarez 84--1.l5 3,007,363 11/1961 Miessner 841.04 X 3,213,197 10/1965 Hawkins.

ALFRED L. BRODY, Primary Examiner. 

